GRADE 6 SCIENCE INSTRUCTIONAL TASKS
Phase Changes
Grade-Level Expectations
The exercises in these instructional tasks address content related to the following science grade-level expectations:
SI-M-A4 Construct, use, and interpret appropriate graphical representations to collect, record, and report data (e.g.,
tables, charts, circle graphs, bar and line graphs, diagrams, scatter plots, symbols) (SI GLE 11)
PS-M-A4 Draw or model the movement of atoms in solid, liquid, and gaseous states (PS GLE 6)
PS-M-A5 Determine the temperatures at which water changes physical phases (e.g., freezing point, melting point,
boiling point) (PS GLE 8)
Contents
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These instructional tasks contain a set of document- or resource-based exercises about phase changes in matter.
Teachers may choose to use or modify the tasks as part of an instructional lesson or as a formative or summative
assessment.
The printable student version excludes teacher directions.
Objective(s)


Model the position and motion of a substance in different phases
Describe the motion of particles in different phases

Apply knowledge of particle movement in solids to real-world
situations
Scaffolding Exercise 3
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
Describe phase changes in a scenario
Write a scientific explanation using appropriate vocabulary
Culminating Exercise


Interpret a graph
Identify and describe processes occurring during phase changes
Scaffolding Exercise 1
Scaffolding Exercise 2
Scoring Rubric
Scoring Notes
Printable Student Version
Teacher Directions
Have students read the text and complete the chart. You may also want students to access outside resources to strengthen their understanding.
Phases of Matter
Scaffolding Exercise 1
Matter occurs in different states or phases including solids, liquids, gases, and plasma. The behavior of the particles of matter differs in each of the
phases. The particles in matter are affected when heat, also called thermal energy, is gained or lost.
A change in the phase of matter can occur if enough energy is added or lost. During the actual phase change, the temperature does not change;
however, intermolecular forces are impacted by the energy transfer. During energy transfer, the particles of matter either move faster and farther
apart or move slower and closer together until the phase change is accomplished.
Task
Draw a model of particle
positions and motion in
each phase of matter in the
boxes provided. Include
nine particles in each
model.
Describe the motion of the
particles in each phase.
Solid
Liquid
Gas
Scaffolding Exercise 2
Teacher Directions: Have students examine the scenario below to respond the prompts that follow.
When engineers design roads and
bridges, they include expansion
joints at key locations. These joints
are necessary for the structures to
remain stable over time.
A. Using your knowledge of
matter and the effects of
thermal energy, describe
why expansion joints are
necessary in large
structures.
B. Structures built in locations with relatively constant temperatures are designed differently than those built in locations with high differences of
temperatures. Explain why this difference is necessary and how climate affects the engineering of large structures.
Teacher Directions:
Have students read the scenario found at http://staff.concord.org/~btinker/workbench_web/states_of_matter/control_nature.html and discuss the
questions with a partner. Then, have students respond to the prompt below.
Student Directions:
Scaffolding Exercise 3
After reading the scenario found at http://staff.concord.org/~btinker/workbench_web/states_of_matter/control_nature.html and discussing the
questions with a partner, write a scientific explanation of the matter changes presented in the scenario. Include the following words in your
explanation: thermal, particles, transfer, energy, solid, liquid, gas.
Write Your Scientific Explanation in the Box Below
Teacher Directions: Have students analyze the graph to respond to the prompts that follow.
100
Temperature (°C)
Culminating Exercise
80
60
40
20
0
-20
-40
Time
A. What is the melting point of the substance? Explain your reasoning.
B. What is the boiling point of the substance? Explain your reasoning.
C. What state of matter is the substance in at 40°C? Explain your reasoning.
D. Determine if this substance is water and provide evidence to support your answer.
Rubric
Key Elements:
A. The response correctly determines the melting point of the substance and explains the reasoning.
B. The response correctly determines the boiling point of the substance and explains the reasoning.
C. The response correctly identifies the state of matter of the substance and explains the reasoning.
D. The response correctly determines if the substance is/is not water and provides evidence to support
the answer.
Response includes all four key elements.
4 Points
Response contains no scientific errors.
Response includes three of the four key elements.
3 Points
Response may include scientific errors.
Response includes two of the four key elements.
2 Points
Response may include scientific errors.
Response includes one of the four key elements.
1 Point
Response may include scientific errors.
A well-developed response should demonstrate a correct and thorough understanding of phase changes. The response should be clear, include specific
details, show a higher level of reasoning skills where appropriate, and address the key elements of the task.
Scoring Notes
Student responses will not be an exact imitation of the responses below. These are given only as examples.
A. According to the graph, the substance starts at a temperature below freezing. The graph shows an increase in temperature until 20°C. Once the
substance reaches that temperature, it changes from a solid to a liquid. This is the melting point of the substance. A phase change is apparent when
the temperature does not increase over a period of time although energy is being added.
B. Once the substance changed from the solid to liquid phase at 20°C, the next phase change should be from liquid to gas. The graph shows an increase
in temperature until 80°C. Once the substance reaches that temperature, it changes from a liquid to a gas. This is the boiling point of the substance.
Again, by looking at the graph there is not an increase in temperature over a period of time which indicates a phase change.
C. The substance is a liquid at 40°C. The substance underwent a phase change at 20°C where it went from the solid to liquid phase. The substance
remains a liquid from 40°C to 80°C.
D. The substance is not water. Water has a melting point of 0°C and a boiling point of 100°C. Since the unknown substance has a different melting and
boiling point as evidenced on the graph, it cannot be water.
Printable
Student Version
Read the text and complete the chart. You may also want to access outside resources to strengthen their understanding.
Phases of Matter
Matter occurs in different states or phases including solids, liquids, gases, and plasma. The behavior of the particles of matter differs in each of the
phases. The particles in matter are affected when heat, also called thermal energy, is gained or lost.
A change in the phase of matter can occur if enough energy is added or lost. During the actual phase change, the temperature does not change;
however, intermolecular forces are impacted by the energy transfer. During energy transfer, the particles of matter either move faster and farther
apart or move slower and closer together until the phase change is accomplished.
Task
Draw a model of particle
positions and motion in
each phase of matter in the
boxes provided. Include
nine particles in each
model.
Describe the motion of the
particles in each phase.
Solid
Liquid
Gas
Examine the scenario below to respond the prompts that follow.
When engineers design roads and
bridges, they include expansion
joints at key locations. These joints
are necessary for the structures to
remain stable over time.
B. Using your knowledge of
matter and the effects of
thermal energy, describe
why expansion joints are
necessary in large
structures.
B. Structures built in locations with relatively constant temperatures are designed differently than those built in locations with high differences of
temperatures. Explain why this difference is necessary and how climate affects the engineering of large structures.
After reading the scenario found at http://staff.concord.org/~btinker/workbench_web/states_of_matter/control_nature.html and discussing the
questions with a partner, write a scientific explanation of the matter changes presented in the scenario. Include the following words in your
explanation: thermal, particles, transfer, energy, solid, liquid, gas.
Write Your Scientific Explanation in the Box Below
Analyze the graph to respond to the prompts that follow.
100
Temperature (°C)
80
60
40
20
0
-20
-40
Time
A. What is the melting point of the substance? Explain your reasoning.
B. What is the boiling point of the substance? Explain your reasoning.
C. What state of matter is the substance in at 40°C? Explain your reasoning.
D. Determine if this substance is water and provide evidence to support your answer.